ByMike Stobbe, Associated PressOctober 30, 2013

The CDC has released the first food allergy guidelines for schools. Peanuts, tree nuts, milk, and shellfish are among the food that most often most trigger reactions. But experts say more than 170 foods are known to cause reactions.

Atlanta — The federal government is issuing its first guidelines to schools on how to protect children with food allergies.

The voluntary guidelines call on schools to take such steps as restricting nuts, shellfish, or other foods that can cause allergic reactions, and make sure emergency allergy medicine – like EpiPens – are available.

About 15 states – and numerous individual schools, or school districts – already have policies of their own. "The need is here" for a more comprehensive, standardized way for schools to deal with this issue, said Dr. Wayne Giles, who oversaw development of the advice for the Centers for Disease Control and Prevention.

Food allergies are a growing concern. A recent CDC survey estimated that about 1 in 20 US children have food allergies – a 50 percent increase from the late 1990s. Experts aren't sure why cases are rising.

Many food allergies are mild and something children grow out of. But severe cases may cause anaphylactic shock or even death from eating, say, a peanut.

The guidelines released Wednesday were required by a 2011 federal law.

Peanuts, tree nuts, milk, and shellfish are among the food that most often most trigger reactions. But experts say more than 170 foods are known to cause reactions.

The new advice call for schools to do such things as:

—Identify children with food allergies.

—Have a plan to prevent exposures and manage any reactions.

—Train teachers or others how to use medicines like epinephrine injectors, or have medical staff to do the job.

—Plan parties or field trips free of foods that might cause a reaction; and designate someone to carry epinephrine.

—Make sure classroom activities are inclusive.

For example, don't use Peanut M&M's in a counting lesson, said John Lehr, chief executive of an advocacy group that worked on the guidelines, Food Allergy Research & Education (FARE).

Carolyn Duff, an elementary school nurse in Columbia, S.C., said she was glad to see the guidelines.

"Many schools may not have policies. And if they do, maybe the policies aren't really comprehensive," said Duff, president of the National Association of School Nurses.

US Rep. Nita Lowey, a New York Democrat who worked on the law that led to the guidelines, said in a statement that they are a big step toward giving parents "the confidence that their children will stay safe and healthy at school."